Mario Alejandro was ready for a fight when he was part of the initial invasion of Iraq in 2003 as a member of the U.S. Marine Corps.

Where he did not expect a fight was at Six Flags Great Adventure while taking his children there for a birthday party.

But due to the shirt that his family bought him for Father’s Day, a fight is exactly what the 33-year-old veteran from Woodbridge says he encountered while attempting to enter the theme park on Saturday.

Alejandro, who is a father of three and a former coach of the Cardinal McCarrick High School football team, served four years as a member of the Marine infantry. He was part of the initial invasion into Iraq in 2003 and said he is classified as disabled, due to the hearing loss and post-traumatic stress disorder he sustained from his military service.

In June, Alejandro’s family gave him several shirts they had purchased from the The Reconnaissance Foundation, a nonprofit organization that helps to support Recon Marines and their families, as a Father’s Day gift for him.

“I thought it was great, I loved it. The shirts fit my personality perfectly. They’re military and they’re patriotic. That’s my thing,” he said. “I wore them to all over the place, to my kids’ baseball games – everywhere. And I got nothing but compliments about how great they were. No one ever said they were offensive, because it’s obvious that they’re in support of the military and the United States.”

But Alejandro said this changed on Saturday when the black shirt he was wearing - with a red, white and blue machine gun and the words "Keep Calm and Return Fire" on the front and the logo and website for The Reconnaissance Foundation on the back - caught the attention of a security guard at the front gate.

Photo of the back of the shirt, which was purchased from the Reconnaissance Foundation, a nonprofit organization that helps to support Recon Marines and their families. Courtesy of Mario Alejandro

“I was walking in through the gate with my wife and kids, who were in front of me, when a security guard grabbed me and said: ‘I can’t let you into the park with that shirt on. That shirt’s offensive,’” Alejandro said on Tuesday. “I said that it’s not offensive, it’s a military shirt. I told him that I am an Iraq veteran… I served in the war. But he said: ‘I don’t care, you have to take that off… or you need to buy another shirt to put over it.’”

Alejandro said that when he refused to take the shirt off or buy a new shirt to cover it, the security guard told him to wait there while he checked with their supervisor.

“I saw him talk to two women in white shirts, who looked at me and then shook their heads. And then the man grabbed my arm and asked me to leave,” he said. “I told them that’s it’s not offensive, that it’s a military shirt and that it means something. But they said: ‘I don’t care, get out of the park."

Alejandro said he complied with the request, but only after announcing to hundreds of other people who were entering the park that he was a veteran and what was happening to him.

"My wife and my son were crying, because they didn't understand why this was happening," he said. "I just told my son to remember this day. To remember how they treat veterans."

Kristin B. Siebeneicher, a spokeswoman for Six Flags Great Adventure, said via email on Thursday that the incident was "under review."

"Our goal is to maintain a fun, safe and family-friendly environment. Our dress code does not permit clothing with vulgar, offensive or violent language or images," she wrote. "If a guest is wearing such attire, we ask them to remove and replace it with another item of clothing; and if they do not have one, they are able to purchase a replacement item at a gift shop."

Siebeneicher added that Six Flags is extremely proud of its longstanding relationship with the U.S. military.

"We work closely with them throughout the season to offer special events that honor our service men and women and their families, including a recent July 4th tribute, and an upcoming 'Salute the Troops' event over the Labor Day weekend," she said. "In addition, active members of the Army, Navy and Air Force helped open our new thrill ride this summer."

But Alejandro said no veteran should ever be treated he way he was on Saturday.

"At the very least should revise their policy," he said. "I fought for this country. I laid in a hole for 36 hours with no sleep, and had friends die for this country and so the people here could have the freedom to things like visit amusement parks. So when they told me that I couldn't come in there with my family because of my shirt - a patriotic shirt - it hurt a lot. No other veteran should ever have to experience that."